HONORS PHYSICAL SCIENCE
Orbitals, Sublevels, and Quantum Numbers Homework
1. What is an orbital?
a region of space around the nucleus of an atom where an electron is most likely to be
found
2. How is it different from an orbit described by Bohr?
it is not a definite location…it is just a probable location
3. Describe how an orbital is related to the electron cloud
the electron cloud is the entire area around the nucleus (the entire football stadium
surrounding the marble). An orbital is a region within the electron cloud where there is a
higher probability of finding electrons that other areas of the electron cloud
4. Define and describe the following terms
a. Principal Energy Levels
the big “rungs on the ladder” of the electron cloud. They are not definite,
however, just the large area where electrons can be found most often
b. Quantum Numbers
a description of the “location” of each electron around the nucleus. This
corresponds with a specific energy for each electron. A different “address” for
each electron.
5. Briefly describe what specific information is given by each of the four quantum numbers.
 principal QN – the main energy level of the electron
 Angular momentum QN – the sublevel within the main energy level that an
electron exists; the “shape” of the orbital
 Magnetic QN – distinguishes between orbitals that have multiple orientations.
there are three p-orbitals in each principal energy level after the first one. Each of
these p-orbitals exists along a different axis (x, y, z). The magnetic QN
distinguishes between the x-axis orbital, the y-axis orbital, and the z-axis orbital.
 Spin QN – only two electrons can exist in each orbital, so there is a need to
distinguish them from each other.
6. What is the principal quantum number?
See above
7. How is it symbolized?
n
8. What information is described by the angular momentum quantum number?
See above
9. How does this relate to sublevels?
Within the main areas of probability (principal energy levels) there are regions of higher
probability (sublevels)
10. What information is described by the magnetic quantum number?
See above
11. How many orbital orientations are possible for the s, p, d, and f sublevels?
See chart from notes (s = 1, p = 3, d = 5, f = 7)
12. Explain how the different orbital orientations are distinguished from one another.
Magnetic quantum number has possible values from –l to + l. because l = 1 for the p
sublevel, the possible values for Magnetic QN are -1, 0, and +1. Each one represents a
p orbital, but on a different axis, i.e. -1 would correspond to the x-axis, 0 would
correspond to the y-axis, and +1 would correspond to the z-axis. This is not an accepted
system…it can change for every different person that is using QN.
13. What information is given by the spin quantum number?
Distinguishing one electron within an orbital from another, s no two electrons can have
the same set of quantum numbers
14. What possible values does the spin quantum number have?
+ ½ and – ½
Angular
Momentum
QN
Magnetic
QN
15. Which quantum number indicates the shape of the orbital?
16. What is the name of the quantum number that indicates the orientation of
the orbital around the nucleus?
2
17. How many possible values are there for the spin quantum number?
+½,-½
18. What are these values?
L
Principal
QN
19. What is the symbol for the angular momentum quantum number?
20. What is the name of the quantum number that describes the main energy
level that an electron occupies?
1
21. How many orientations can an s orbital have around the nucleus?
22. What is the name of the quantum number that indicates the spin states of
an electron within an orbital?
Spin QN
Spherical
(s orbital)
23. What shape corresponds to l = 0?
m (or ml)
24. What is the symbol of the magnetic quantum number?
3
25. How many orbital shapes exists within energy level n = 3?
s, p, d
“dumbbell”
(p orbital)
4 (s, p, d,
f)
26. What are these shapes?
27. What shape corresponds to l = 1?
28. How many orbital shapes exist in the fourth energy level (n = 4)?
n
29. What is the symbol for the principal quantum number?
30. How many quantum numbers are needed to describe the “location” (or
energy state) of an electron?
4
5 (see
chart in
notes)
3 (see
chart in
notes)
31. How many different orientations are there for the d sublevel?
32. How many different orientations are there for the p sublevel?
33. How many orbital shapes exists within the second energy level (n = 2)?
2 (s, p)
2
4 (1 s
orbital, 3 p
orbitals)
9 (1 s, 3 p,
5 d)
See cart
below
Orbital
number
Type of
orbital
Principal
QN
Angular
34. How many electrons can a single orbital hold?
35. What is the total number of orbitals in the second energy level (n = 2)?
36. What is the total number of orbitals in the third energy level (n = 3)?
37. What would be the first three quantum numbers for EACH of these orbitals?
1
2
3
4
5
6
7
8
9
s
p
p
p
d
d
d
d
d
3
3
3
3
3
3
3
3
3
0
1
1
1
2
2
2
2
2
Momentum
QN
Magnetic
QN
0
-1
0
1
-2
-1
0
1
2